Use -Werror in frameworks/native/libs/vr

* Suppress/fix warnings of unused variable, parameter,
  private-field, and function.
* Fix warnings about typedef missing declarator.
* Use -Wno-error to keep existing warnings, to fix later.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Iae96af3f6a17623befe73a9db2c81275fee44fa6
diff --git a/libs/vr/libbufferhubqueue/tests/Android.bp b/libs/vr/libbufferhubqueue/tests/Android.bp
index 865573c..5a3c3a6 100644
--- a/libs/vr/libbufferhubqueue/tests/Android.bp
+++ b/libs/vr/libbufferhubqueue/tests/Android.bp
@@ -28,6 +28,9 @@
         "-DTRACE=0",
         "-O0",
         "-g",
+        "-Wall",
+        "-Werror",
+        "-Wno-error=sign-compare", // to fix later
     ],
     name: "buffer_hub_queue-test",
     tags: ["optional"],
@@ -42,6 +45,8 @@
         "-DTRACE=0",
         "-O0",
         "-g",
+        "-Wall",
+        "-Werror",
     ],
     name: "buffer_hub_queue_producer-test",
     tags: ["optional"],